Sucrose crystal growth. II. Rate of crystal growth in the presence of impurities

Smythe, B.M.

doi:10.1071/ch9671097

Cited by 48 publications

(39 citation statements)

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“…The effects of other components, e.g. soluble proteins and salts, on vitrification were not tested; however, Smythe (9) found that the crystallization of sucrose was not impeded significantly by organic acids and salts; the most effective inhibitors of sucrose crystallization were oligosaccharides. This implies that not all cell components can interrupt the crystalline matrix of sucrose, and that raffinose may be necessary to ensure the formation of a glass rather than a crystal during drying.…”

Section: Methodsmentioning

confidence: 99%

Glass Formation and Desiccation Tolerance in Seeds

Koster¹

1991

Plant Physiol.

243

158

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The formation of intracellular glass may help protect embryos from damage due to desiccation. Soluble sugars similar to those found in desiccation tolerant embryos were studied with differential scanning calorimetry. Those sugars from desiccation tolerant embryos can form glasses at ambient temperatures, whereas those from embryos that do not tolerate desiccation only form glasses at subzero temperatures. It is concluded that tolerant embryo cells probably contain sugar glasses at storage temperatures and water contents, but intolerant embryo cells probably do not.The ability to survive the desiccated state is the result of adaptations that prevent cellular destruction during the withdrawal of water. As water leaves a cell that does not tolerate desiccation, many events occur: solutes become more concentrated, possibly increasing the rate of destructive chemical reactions; some solutes may crystallize, changing the ionic strength and pH ofthe intracellular solution; proteins become denatured, many irreversibly; and membranes become disrupted, leading to the loss of compartmentation. It has been suggested that the presence of large amounts of soluble sugars within a cell can prevent the damaging effects of desiccation (2). Soluble sugars are known to form hydrogen bonds and thus may substitute for water in maintaining hydrophilic structures in their hydrated orientation, even when water is no longer present (2). Water replacement by soluble sugars has been demonstrated in model systems, where soluble sugars were able to preserve the functional integrity, measured as Ca2+-ATPase activity, of desiccated microsomes through a dehydration/rehydration cycle (2).Another mechanism by which sugars may act to protect the cell during desiccation is by the formation of an intracellular glass (5 the solution is called a glass. A glass is essentially an undercooled liquid; therefore, its existence is temperature dependent. A solution that exists as a glass at one temperature will melt at a higher temperature, giving rise to a liquid and the possibility of crystallization (3).The benefits of glass formation, or vitrification, to an organism undergoing water loss are many. Glasses preclude chemical reactions requiring diffusion, thus ensuring stability during a period of dormancy; they fill space, and thus by sheer bulk may prevent cellular collapse; an amorphous glass may trap chaotropic solutes, preventing their becoming concentrated; and glasses may permit the continuance of hydrogen bonding at the interface between the glass and hydrophilic surfaces in the cell (1). These properties would help ensure the survival of an organism during a period of desiccation.Using DSC3, Williams and Leopold (10) found evidence of a glass-like state in desiccated corn embryos. Transitions similar to those made by glasses were detected in both the lipid and nonlipid portions of the embryo, and it was hypothesized that the soluble sugar component of the embryo was responsible for the nonlipid glass transition (10). Soluble sugars compri...

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Section: Methodsmentioning

confidence: 99%

Glass Formation and Desiccation Tolerance in Seeds

Koster¹

1991

Plant Physiol.

243

158

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“…In addition this attachment does not induce any raffinose XRD peaks (Vaccari et al, 1986;Mantovani et al, 1977;1983;Mathlouthi and Reiser, 1995). Smythe (1967) and Iglesias et al(2000) also found that raffinose slows the crystallization of sucrose in aqueous solutions and that the optimal equilibrium state of crystalline raffinose is as a pentahydrate form, therefore, a relatively large amount of water is needed to completely crystallize it. Pure raffinose also has a higher glass transition temperature as compared to pure sucrose and may work in the same way trehalose inhibited crystallization of sucrose as found by Roe and Labuza (2006).…”

Section: Introductionmentioning

confidence: 99%

Crystallization inhibition of an amorphous sucrose system using raffinose

Leinen

Labuza

2006

J. Zhejiang Univ. - Sci. B

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Abstract:The shelf life of pure amorphous sucrose systems, such as cotton candy, can be very short. Previous studies have shown that amorphous sucrose systems held above the glass transition temperature will collapse and crystallize. One study, however, showed that adding a small percent of another type of sugar, such as trehalose, to sucrose can extend the shelf life of the amorphous system by slowing crystallization. This study explores the hypothesis that raffinose increases the stability of an amorphous sucrose system. Cotton candy at 5 wt% raffinose and 95 wt% sucrose was made and stored at room temperature and three different relative humidities (%RH) 11%RH, 33%RH, and 43%RH. XRD patterns, and glass transition temperatures were obtained to determine the stability as a function of %RH. The data collected showed that raffinose slows sucrose crystallization in a low moisture amorphous state above the glass transition temperature and therefore improves the stability of amorphous sucrose systems.

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Section: Introductionmentioning

confidence: 99%

“…In addition, sucrose has been shown to protect soluble enzymes from salt-induced damage in vitro (32). The presence of a larger oligosaccharide along with sucrose may enhance protection still further by favoring vitrification rather than crystallization (6,9,17,33,35).Although oligosaccharides such as stachyose have been recognized as protective agents in leaves against cold-induced damage, they are often referred to as a carbon reserve for germination rather than as a desiccation protectant in the axes of nonendospermic legume seeds (12). Raffinose and stachyose are synthesized by the following reactions (12) catalyzed by galactinol synthase (UDP-galactose:inositol galactosyltransferase) (Eq.…”

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confidence: 99%

Maturation Proteins and Sugars in Desiccation Tolerance of Developing Soybean Seeds

Sa¹,

Rl²,

Ac³

1992

Plant Physiol.

319

198

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The desiccation-tolerant state in seeds is associated with high levels of certain sugars and maturation proteins. The aim of this work was to evaluate the contributions of these components to desiccation tolerance in soybean (Glycine max [L.] Merrill cv Chippewa 64). When axes of immature seeds (34 d after flowering) were excised and gradually dried (6 d), desiccation tolerance was induced. By contrast, seeds held at high relative humidity for the same period were destroyed by desiccation. Maturation proteins rapidly accumulated in the axes whether the seeds were slowly dried or maintained at high relative humidity. During slow drying, sucrose content increased to five times the level present in the axes of seeds held at high relative humidity (128 versus 25 pg/axis, respectively). Stachyose content increased dramatically from barely detectable levels upon excision to 483 pg/axis during slow drying but did not increase significantly when seeds were incubated at high relative humidity. Galactinol was the only saccharide that accumulated to higher levels in axes from seeds incubated at high relative humidity relative to axes from seeds that were slowly dried. This suggests that slow drying serves to induce the accumulation of the raffinose series sugars at a point after galactinol biosynthesis. We conclude that stachyose plays an important role in conferring desiccation tolerance.The remarkable mechanism that allows most mature angiosperm seeds to survive desiccation to extremely low water contents is poorly understood. Among the protective components that have been proposed to be important in the acquisition of desiccation tolerance during seed development are proteins and soluble sugars. The group of proteins known as Late Embryogenesis Accumulating, or Lea (13), proteins include some that accumulate during the maturation drying phase of seed development. Some of these maturation proteins have been correlated with the ability of the seed to progress into seedling growth (29), whereas others have been correlated with desiccation tolerance (2, 4). However, some additional process is apparently necessary for the development of desiccation tolerance. We have shown that maturation protein accumulation alone is not sufficient to confer desiccation tolerance in developing soybean (4 characteristic of mature orthodox seeds (1). They have been implicated by correlation as adaptive agents for desiccation tolerance during seed development and germination (9,18,19). In particular, cultivars of soybean (Glycine max) accumulate high levels of the raffinose series of oligosaccharides, particularly stachyose, in addition to sucrose (12,18,21,31). Evidence for the protective role of soluble sugars has also been inferred from model systems (7, 11). The soluble sugar, trehalose, protects cytosolic components in yeast against desiccation-, frost-, and heat-induced damage in vivo (34). It is thought that the hydroxyl constituents of sugars may replace the hydration shell around membranes and thus prevent structural damage a...

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Sucrose crystal growth. II. Rate of crystal growth in the presence of impurities

Cited by 48 publications

References 0 publications

Glass Formation and Desiccation Tolerance in Seeds

Glass Formation and Desiccation Tolerance in Seeds

Crystallization inhibition of an amorphous sucrose system using raffinose

Maturation Proteins and Sugars in Desiccation Tolerance of Developing Soybean Seeds

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